Electromagnetic riveting machine

ABSTRACT

An electromagnetic riveting machine comprising a hand-held selectively actuatable electromagnet having means to support a rivet relative to a striker bar positionable on the opposite side of the workpiece from the electromagnet. The striker bar comprises a metal bar pivotally held within a metal frame and biased away from the work surface by a flat spring member acting against the frame. If desired, a permanent magnet may be attached to each of the portions of the tool so as to ensure proper placement thereof relative to one another.

United States Patent Seekins [451 Oct. 3, 1972 [54] ELECTROMAGNETICRIVETING MACHINE [72] Inventor: William C. Seekins, Los Angeles,

Calif.

[73] Assignee: Hughes Tool Co., Aircraft Division, Culver City, Calif.

[22] Filed: April 8, 1970 [21] Appl. No.2 26,582

[52] US. Cl, ..72/430, 72/445, 72/446, 7 227/ 131 [51] Int. Cl. ..B2lj15/24 [58] Field of Search....l8/DlG. 33', 72/430, 445, 446, 72/416;227/131; 29/243.53, 243.54

[56] References Cited UNITED STATES PATENTS 2,752,061 6/1956 Michlein..227/131 X 2,088,350 'I/l937 Shanks et a1 ..227/l3l Shafi' ..72/416 X2,313,843 3/ l 943 3,581,373 6/ 1971 Murdoch et a]. ..29/243.543,600,928 8/ 1971 Retherford ..'.....72/452 X Primary Examiner-J.Spencer Overholser Assistant Examiner-John E. Roethel Attorney-Smyth,Roston & Pavitt [57] ABSTRACT An electromagnetic riveting machinecomprising a hand-held selectively actuatable electromagnet having 5Claims, 3 Drawing Figures 1 ELECTROMAGNETIC RIVETING MACHINE BACKGROUNDOF THE lNVENTlON deformed or upset so that it spreads radially beyondthe adjacent hole diameter so that it cannot be removed therefrom.

In prior art devices, rivets have normally been put into position in twoways. In the oldest method, the rivet is positioned in the-aligned holesand a large, heavy bucking bar is positioned against the headed end ofthe rivet and a pneumatic rivet gun is used to deform the other end ofthe rivet.

This method is satisfactory in a large number of applications, butdepends upon the availability of space for the positioning and holdingof the bucking bar. When space is not available, the method cannot beutilized.

The inherent difficulty found in the older method has been solved to agreat extent through the use of what has become known as blind rivets.Such rivets are SUMMARY OF THE INVENTION The present invention relatesto an electromagnetic riveting machine capable of upsetting standardrivets.

, Further, the machine is capable of upsetting such rivets in otherwiseinaccessible places and can be manufactured to be much smaller andlighter than previously available pneumatic riveting guns.

Basically, the machine comprises two elements, one of which ispositioned on each side of the structure which is to be riveted. Oneelement consists of a selectively actuatable electromagnet to which arivet support is attached. The second element comprises a striker barwhich is held in a position away from the .structure to be riveted by aspring acting between the bar and a supporting wire frame.

In use, the first element is positioned on one side of a workpiece sothat the rivet support holds the headed end of a standard rivet inaligned holes and, in effect,

acts as a bucking bar. The second element is positionedon the oppositeside of the workpiece so that a free end of the striker bar ispositioned above the end of the rivet which is to be upset. The electromagnet in the first element is actuated, creating a magnetic field whichacts upon the striker bar to draw it toward the electromagnet, andconsequently the rivet, against the force of the spring. The weight andmass previously required in pneumatic riveting guns is effectivelyreplaced by the momentum of the striker bar as it impacts the free endof the rivet. Cyclic actuation of the electromagnet causes repetitiveupsetting strokes by the striker bar until the rivet is fully upset.

If desired, a permanent magnet may be mounted upon the second elementsupporting frame to cooperate with either a second permanent magnet or asecond electromagnet on the first element so as to be able to positionthe elements relative to one another in blind areas.

The use of structure embodying the concepts of the present inventionallows rivets to be upset very quickly, and allows strong riveting inpreviously inaccessible areas. Additionally, the riveted structure willbe stronger than heretofore possible since the standard rivetprovides'greater strength than is available with the well-known,hollow-shanked blind rivet. As an added feature, use of a machineembodying this invention will allow less expensive fabrication ofriveted structures which would otherwise be possible with the useof-blind rivets since standard rivets are less expensive than blindrivets.

Other advantages, objects, modes, and embodiments of this invention willbecome obvious to those skilled in the art through reference totheDetailed Description and accompanying drawing which illustrate whatare presently considered to be preferred embodiments of the best modecontemplated for utilizing the novel principles of the invention whichis intended to be limited only by the recitation of the claims.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side elevation of a firstembodiment of the electromagnetic riveting machine formed in accordancewith the present invention;

FIG. 2 is a perspective illustration of one element of the machine shownin FIG. 1'; and

FIG. 3 is a plan view of an alternate embodiment of a machine formed inaccordance with the present invention.

DETAILED DESCRIPTION pivotally supports a striker bar 29 for movementtoward and away from the rivet 23. A leaf spring 31 is suitably fixed tothe bar 29 by means such as screws or rivets 33. The spring acts againsta transverse member of the frame 27 so as to bias the striker bar 29 tothe position illustrated in FIGS. 1 and 2.

In use, an operator inserts the rivet 23 into the aligned holes in theworkpiece 25 and then positions the electromagnet element so that therivetsupport 19 holds the head end of the rivet as shown and acts as abucking bar.

The striker bar element is positioned on the opposite side of thestructure to be riveted so that the free end of the bar is positionedover the shank of the rivet. i

The electromagnet 11 is then actuated by the operation of trigger l7,causing a magnetic field to be created which acts upon the striker bar29 so as to draw it into upsetting contact with the rivet 23 in a veryrapid pivoting motion relative to the frame 27.

When trigger 17 is released, the striker bar will return to' theillustrated position due to the influence of spring 31. Repeatedoperation of trigger 17 will result ina like number of strokes by thestriker bar 29 .until the shank of the rivet 23 is fully upset and thenext rivet can be put into place.

The embodiment-of the invention illustrated in FIG. 3, has'a great dealof structure which is identical to that found in the previouslydescribed embodiment. That structure which is identical has beenprovided with identical labels preceded by the numeral 1"; electromagnet11 therefore becomes 111, etc. No further description is'deemednecessary.

As shown, the electromagnet 111 has a rivet support 151 thereon having arecessed portion 153 for the support of the head of a rivet 154 which isnot meant to be flush with the surface ofthe adjacent workpiece 125.

A striker bar 155 is pivotally supported on the frame 127 and has anupsetting recess 157 at the free end thereof so as to control the amountof upsetting of the shank of the rivet. In other words, the recess 157will prevent the shank from being upset to a degree greater than thatdetermined to be necessary when the structure to be riveted is designed.

An auxiliary frame 161 is suitably fastened to the frame 127 or thestriker bar 155 so that a permanent magnet 163 is suitably supportedrelative to the striker bar. a

An arm 165 mounted on the handle 113 supports a magnet 167 which may beeither a permanent magnet or may be a second electromagnet which isselectively actuated'either by the trigger 117 or by other suitablemeans.

Magnets 163 and 167 are suitably positioned, by auxiliary frame 161 andarm 165 so that they cooperate with one another to ensure the properalignment of the electromagnet and the striker bar elements. Thus, forexample, if the electromagnet element is held against the adjacentworkpiece 125 and moved in a direction parallel to the surface thereof,the striker bar 155 will be moved in a similar direction and distancesince the magnet l63 will tend to follow the magnet 167.

In manufacturing machines utilizing the concepts of the presentinvention, it will be apparent to those skilled in the art that theelectromagnet actuating trigger could be replaced by an automatictriggering mechanism which will produce far more rapid movementof thestriker bar. Further, a rheostat could be added to the system so thatthe strength of the magnetic field generated by the electromagnet couldbe adjusted was to take into account the characteristics of theworkpieces .which are to be riveted. Additionally, the elements could becoated with a suitable substance, such 'as Teflon, to prevent scratchingof the surfaces of the workpieces and to aid in dragging the striker barinto position, e. g., when the embodiment shown in FIG. 3 is utilized.

Thus, the applicant has disclosed two embodiments of new and improvedconcepts in machines which may be utilized in the riveting art and whichyield a true advance in tl}at art. Maggdfurther modifi ations andalterations 0 these em iments, as we] as other embodiments, will beobvious to those skilled in the art without exceeding the scope of theinvention which is defined in the following claims:

I claim:

1. In a machine for fixing a rivet to structure comprising one or moreworkpieces with a rivet head on one side of the structure and an upsetportion on the other side thereof,

a first element having means for supporting the headed end of the rivet,means for creating an electromagnetic field, and means for activatingand deactivating said electromagnetic field and a second element havinga supporting frame,

a magnetically attractable striker bar pivotally mounted in saidsupporting frame, and a biasing means between said supporting frame andsaid striker bar and biasing said striker bar to a position away fromthe end of a rivet to be upset. 2. The machine of claim 1 wherein saidfirst element further includes alignment means thereon and said secondelement further includes I alignment means thereon which cooperate withsaid first element alignment means to properly align said first andsecond elements relative to one another and to a rivet to be upset. 3.The machine of claim 2 wherein said first element alignment means andsaid second element alignment means both comprise magnetic elementssuitably aligned to be mutually attractive. 4. The machine of claim 1wherein said striker bar includes an upsetting surface thereon and meansfor limiting the upsetting of a rivet by limiting the pivotal travel ofsaid upsetting surface. 5. A riveting machine comprising a first elementhaving means for generating an electromagnetic force field and I meansfor supporting one end of a rivet relative to workpieces to be fastenedtogether by a rivet and a second element having means, responsive to anelectromagnetic force field, for moving toward and upsetting the otherend of a rivet supported by said first element and means for biasingsaid upsetting means away from a rivet supported by said first element,said first and second elements each including a magnetic locating andpositioning member thereon for ensuring proper positioning of said firstand second elements relative to a rivet to be upset and to one another.

1. In a machine for fixing a rivet to structure comprising one or moreworkpieces with a rivet head on one side of the structure and an upsetportion on the other side thereof, a first element having means forsupporting the headed end of the rivet, means for creating anelectromagnetic field, and means for activating and deactivating saidelectromagnetic field and a second element having a supporting frame, amagnetically attractable striker bar pivotally mounted in saidsupporting frame, and a biasing means between said supporting frame andsaid striker bar and biasing said striker bar to a position away fromthe end of a rivet to be upset.
 2. The machine of claim 1 wherein saidfirst element further includes alignment means thereon and said secondelement further includes alignment means thereon which cooperate withsaid first element alignMent means to properly align said first andsecond elements relative to one another and to a rivet to be upset. 3.The machine of claim 2 wherein said first element alignment means andsaid second element alignment means both comprise magnetic elementssuitably aligned to be mutually attractive.
 4. The machine of claim 1wherein said striker bar includes an upsetting surface thereon and meansfor limiting the upsetting of a rivet by limiting the pivotal travel ofsaid upsetting surface.
 5. A riveting machine comprising a first elementhaving means for generating an electromagnetic force field and means forsupporting one end of a rivet relative to workpieces to be fastenedtogether by a rivet and a second element having means, responsive to anelectromagnetic force field, for moving toward and upsetting the otherend of a rivet supported by said first element and means for biasingsaid upsetting means away from a rivet supported by said first element,said first and second elements each including a magnetic locating andpositioning member thereon for ensuring proper positioning of said firstand second elements relative to a rivet to be upset and to one another.